Effects of fasting and refeeding on plasma concentrations of leptin, ghrelin, insulin, growth hormone and metabolites in swine.

摘要

The effects of nutritional status, such as fasting and refeeding, on leptin and ghrelin secretion in swine were examined. The swine (n=4) were fasted for 54 h and plasma hormone levels were measured before, during and after fasting. Plasma leptin and insulin concentrations began to decrease 12 and 6 h into the fasting period, respectively (P<0.05), and maintained a low level for the remaining period of fasting. Plasma leptin and insulin returned to the pre-fasting value 6 and 12 h after refeeding, respectively. Plasma ghrelin concentrations showed a nocturnal periodicity during the fasting period; it increased nocturnally at 36 and 42 h into the fasting period (P<0.05). Plasma growth hormone levels did not show any remarkable changes during the fasting. Plasma glucose levels showed a modest fall during fasting and significantly decreased (P<0.05) at 24 h into the fasting period, returning to pre-fasting levels after refeeding. Plasma nonesterified fatty acid levels increased (P<0.05) at 12 h into the fasting period and returned to the pre-fasting level 6 h after refeeding. These results indicate that plasma leptin, insulin and ghrelin play an important role in maintaining energy homeostasis in swine. The plasma ghrelin did not continuously increase, but showed nocturnal periodicity during fasting. This may suggest that ghrelin is also involved in physiological processes other than energy homeostasis..